Yamaha F150 rpm problem

[jmoran]

I have a 2006 F150 with 550 hours on it. I bought it used and found out after I bought it that it will only tach to 5400 rpm's. I have cleened the injectors, changed plugs, changed fuel filters, run yamaha combustion chamber cleaner throug it, run a leakdown test three time throught the cleaning process and checked the valve lash. # 1&4 cilinders have 4 lbs of leakdown at 90 lbs supply #2 has 20 lbs and #3 has 30 lbs. I have been told to shock it with yamaha ring free 32 oz in a small gas can. I think the problem is in hte valves but not positive. I am passing air from #3 to #1 cilinder when I run the leakdown test. I don't know where the air for #2 cilinder is going I didn't pull the intake off after I ran the boat last.
Any ideas on this woud be appreciated.

 

[Home Cookin']

Re: Yamaha F150 rpm problem

I'm not the expert but I think you are close to your top end at 5400. Have you checked your prop and adjusted trim settings while running? Check the specs for that hull and motor? I am suspecting the prop unless the stuff you described is something the experts would say is relevant.